Question from Pittsburgh, Pennsylvania, USA:

My 29-month-old daughter was visiting my mother-in-law recently. My mother-in-law, sister-in-law, and brother-in-law are all type 1 diabetics. My mother-in-law decided to test my daughter’s blood about one-half hour after she drank some juice on an empty stomach; she was 287 mg/dl [15.9 mmol/L]. A half hour later, she was 155 mg/dl [8.5 mmol/L]. We took her to a doctor, who ordered blood drawn and a blood sugar level test done, which registered at 89 mg/dl [4.9 mmol/L]. They also did a urine test and the results came back normal. Over the next couple of days, we monitored my daughter’s morning fasting numbers (all in the 80s mg/dl [4.4 to 4.9 mmol/L]), as well as her levels two hours after meals (all in the 80s mg/dl [4.4 to 4.9 mmol/L]). However, my mother-in-law tested her within an hour after meals a couple of times and she registered 206 mg/dl [11.4 mmol/L] and 269 mg/dl [14.9 mmol/L] on those tests. Are high readings like this normal within an hour after a meal or is this a sign of diabetes/pre-diabetes? She has no other symptoms (no excessive thirst or urination, no fatigue, etc.).